KR20210031239A - System and method for blocking unauthorized line in passive optical network - Google Patents

Abstract

Disclosed are a system and method for detecting and blocking an optical signal coming from an unauthorized line in a passive optical network (TDM-PON) of a time division multiplexing scheme so as to prevent a failure caused by the unauthenticated line from being spread to all subscriber lines. According to one embodiment, the system for detecting and blocking an unauthorized line in a passive optical network comprises: a blocking device including a plurality of ports connected to a plurality of optical subscriber terminals, and configured to supply power to the plurality of optical subscriber terminals so as to operate the plurality of ports in a blocking mode or a pass-through mode; and an optical line terminal configured to control the blocking device to cut off power to the plurality of optical subscriber terminals, set the plurality of ports to the blocking mode, temporarily set each of the plurality of ports to a pass-through mode sequentially to detect whether an uplink optical signal is received, and determine that an optical subscriber terminal connected to a port from which the uplink optical signal is received is an unauthenticated line.

Description

System and method for blocking unauthenticated lines in passive optical networks {SYSTEM AND METHOD FOR BLOCKING UNAUTHORIZED LINE IN PASSIVE OPTICAL NETWORK}

The present invention relates to a passive optical network (PON) technology, and more specifically, to a time division multiple access method of passive optical network (Time Division Multiple Access-PON) technology.

The high-speed Internet infrastructure currently being built nationwide is applying passive optical network (PON) technology. The passive optical network is a network that connects offices and subscribers in a point-to-multi-point method, and is economical because it can reduce the number of office systems and optical cables required compared to a structure having a one-to-one connection structure. Currently, TDMA-PON (Time Division Multiple Access-PON), which is an ultra-high-speed optical network with a time division multiple access method such as EPON (Ethernet PON) and GPON (Gigabit Capable PON), is widely spread all over the world. In particular, GPON was spread to many regions around the world. In 2010, ITU-T, the telecommunication standardization division of the International Telecommunication Union, completed the G.987 XG-PON standard recommendation, which is a 10G-GPON. Are being released. Since the passive optical network has a point-to-multipoint structure, it is difficult to guarantee quality and security at the same time in the transmission layer of the passive optical network. In other words, because the passive optical network is a point-to-multipoint communication structure, failure propagation can occur. There is a difficult point.

The present invention has been proposed to solve the above-described problem. In a time division multiple access passive optical network (TDMA-PON), by detecting and blocking an optical signal from an unauthenticated line, all subscriber lines are prevented from failure due to an unauthenticated line. It is an object of the present invention to provide a system and a method for preventing the spread of the system.

According to an embodiment, a system for detecting and blocking an unauthorized line in a passive optical network includes a plurality of ports connected to a plurality of optical subscriber terminals, supplies power to the plurality of optical subscriber terminals, and supplies power to the plurality of optical subscriber terminals. A blocking device that operates the port in a blocking mode or a pass-through mode; And controlling the blocking device to cut off power to the plurality of optical subscriber terminals and set the plurality of ports to a blocking mode, and then temporarily set each of the plurality of ports to a pass mode sequentially to receive an uplink optical signal. And an optical line terminal that detects whether or not an optical subscriber terminal connected to a port on which an uplink optical signal is received is an unauthenticated line.

The blocking device may include a power supply for supplying power to the plurality of optical subscriber terminals; An optical attenuator provided in each of the plurality of ports to perform the blocking mode or the pass mode; And a splitter that aggregates uplink optical signals received from the plurality of optical subscriber terminals and transmits them to the optical line terminal, and distributes the downlink optical signals received from the optical line terminals to the plurality of optical subscriber terminals. .

The optical line terminal may maintain a port determined to be an unauthenticated line in a blocking mode, and set ports of the remaining lines in a pass mode.

The optical line terminal may determine a simple transmission error when the unauthenticated line is in a normal open state and the MAC address detected from the optical subscriber station of the unauthenticated line matches the previously opened MAC address.

The optical line terminal, when the unauthenticated line is not in a normal open state, or when the MAC address detected from the optical subscriber terminal of the unauthenticated line does not match the previously opened MAC address, It can be determined as an authentication line.

When the loss rate or error rate of a packet received from the blocking device or a packet transmitted to the blocking device is greater than or equal to a threshold value, the optical line terminal may start detecting and blocking an unauthenticated line.

A method of detecting and blocking an unauthenticated line in a passive optical network according to an embodiment includes a plurality of ports connected to a plurality of optical subscriber terminals, supplies power to the plurality of optical subscriber terminals, and connects the plurality of ports. Controlling a blocking device operating in a blocking mode or a pass mode to cut off power to the plurality of optical subscriber terminals; Setting the plurality of ports of the blocking device to a blocking mode; Temporarily setting each of the plurality of ports of the blocking device to a pass mode sequentially to detect whether an uplink optical signal is received; And determining an optical subscriber terminal connected to the port on which the uplink optical signal is received as an unauthenticated line.

The blocking device may include a power supply for supplying power to the plurality of optical subscriber terminals; An optical attenuator provided in each of the plurality of ports to perform the blocking mode or the pass mode; And a splitter that aggregates uplink optical signals received from the plurality of optical subscriber terminals and transmits them to an optical line terminal, and distributes the downlink optical signals received from the optical line terminals to the plurality of optical subscriber terminals.

The determining may include maintaining a port determined as an unauthenticated line in a blocking mode and setting the ports of the remaining lines in a pass mode.

The determining may include determining as a simple transmission error when the unauthenticated line is in a normal open state and the MAC address detected from the optical subscriber terminal of the unauthenticated line matches the previously opened MAC address. have.

In the determining step, when the unauthenticated line is not in a normal open state, or when the MAC address detected from the optical subscriber station of the unauthenticated line does not match the previously opened MAC address, the unauthenticated line is finally in the unauthenticated state. It may include the step of determining the authentication line.

The method may further include initiating an operation of detecting and blocking an unauthenticated line when a loss rate or an error rate of a packet received from the blocking device or a packet transmitted to the blocking device is greater than or equal to a threshold value.

According to the present invention, by detecting and blocking an optical signal flowing from an unauthenticated line in a passive optical network, it is possible to prevent a failure due to an unauthenticated line from spreading to all subscriber lines.

In addition, the present invention distinguishes whether an unauthenticated line is detected by a simple transmission error or an unauthenticated subscriber terminal when detecting an unauthenticated line in a passive optical network, thereby increasing the accuracy of determining an unauthenticated line and improving the quality of service.

1 is a diagram showing an unauthenticated line blocking system in a TDM-PON environment according to an embodiment of the present invention.
FIG. 2 is a diagram showing the configuration of the blocking device of FIG. 1.
3 is a flowchart illustrating a method of detecting and blocking an unauthorized line in an OLT according to an embodiment of the present invention.
4 is a flowchart illustrating a method of detecting and blocking an unauthorized line in an OLT according to another embodiment of the present invention.

The above-described objects, features, and advantages will become more apparent through the following detailed description in connection with the accompanying drawings, whereby those of ordinary skill in the technical field to which the present invention pertains can easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram showing an unauthenticated line blocking system in a TDMA-PON environment according to an embodiment of the present invention. Referring to FIG. 1, an unauthenticated line blocking system according to the present embodiment includes an optical line terminal (OLT, hereinafter referred to as OLT) 110, a blocking device 120, and a plurality of optical subscriber terminals. Network Unit/Optical Network Terminal: ONU/ONT, hereinafter referred to as ONT) 130. In this embodiment, ONU and ONT are collectively described as ONT. ONU is a device that is installed at the entrance of a dense subscriber group such as an apartment to accommodate the function of converging multiple subscriber lines, and ONT is a device that accommodates a single subscriber. Since both ONU and ONT are equipment accommodating subscribers, they are collectively referred to as ONT in this embodiment.

The OLT 110 is connected to a backbone network of a central office, such as a telephone office, and serves to terminate an optical signal within the telephone office. The OLT 110 transmits a downlink optical signal to the plurality of ONTs 130 and receives an uplink optical signal generated by the plurality of ONTs 130. The ONT 130 is a subscriber end point, and a plurality of ONTs 130 are connected to one OLT 110 to form a point-to-multipoint structure. In this embodiment, the blocking device 120 is included between the OLT 110 and the plurality of ONTs 130. The OLT 110 controls the blocking device 120 to detect and block an unauthenticated line among the plurality of ONTs 130.

The OLT 110 transmits an OLT laser diode serving as a transmission of a downlink optical signal, an OLT photodiode serving as a reception of an upstream optical signal, and a downlink optical signal to be transmitted from the OLT laser diode. An OLT transceiver including a converter that converts and converts an optical signal received through the OLT photodiode to optical/electric (optic to electric), a communication module for data communication with the blocking device 120, and overall operation control It may include a processor that performs. The processor of the OLT 110 starts detecting and blocking unauthenticated circuits when the ingress and engress packet loss rate or the cyclic redundancy check (CRC) error rate exceeds a predetermined criterion. Hereinafter, a method of detecting and blocking an unauthenticated line will be described in more detail.

FIG. 2 is a diagram showing the configuration of the blocking device of FIG. 1. Referring to FIG. 2, the blocking device 120 includes a power supply 210, a splitter 220, a communication unit 230, a control unit 240, and a plurality of ports 250.

The power supply 210 is connected to the plurality of ONTs 130 to remotely supply power to the plurality of ONTs 130. The power supply 210 may be connected to a commercial power source or a separate battery to supply power to the plurality of ONTs 130.

The splitter 220 is a passive splitter, and branches the downlink optical signal received from the OLT 110 to a plurality of ONTs 130, and focuses the uplink optical signal received from the plurality of ONTs 130 to focus the OLT 110. ). More specifically, the splitter 220 divides the downlink optical signal received from the OLT 110 to a plurality of ports 250, and focuses the uplink optical signal received from the plurality of ports 250 to the OLT ( 110).

The communication unit 230 communicates with the OLT 110. The communication unit 230 may communicate with the OLT 110 through a different communication path than the connection between the OLT 110 and the plurality of ONTs 130. The communication unit 230 receives a control command for detecting the ONT 130 of an unauthenticated line among the plurality of ONTs 130 from the OLT 110, transmits it to the control unit 240, and controls it from the control unit 240 Receives the execution result of the command and transmits it to the OLT (110).

Each of the plurality of ports 250 is connected to each of the plurality of ONTs 130 and transmits a downlink optical signal transmitted from the OLT 110 to the corresponding ONT 130, and upwards from the corresponding ONT 130 The optical signal is received and transmitted to the splitter 220. Each of the plurality of ports 250 includes an optical attenuator that constantly or continuously reduces the intensity of an optical signal, and each of the plurality of ports 250 controls the optical attenuator under the control of the controller 240 Thus, the optical signal passing mode or blocking mode is operated. In the pass mode, the optical attenuator passes through without reducing the intensity of the optical signal, and in the blocking mode, the optical attenuator reduces the intensity of the optical signal and blocks the optical signal from passing.

The control unit 240 receives a control command for detecting and blocking an unauthenticated line from the OLT 110 through the communication unit 230, and according to the control command, the power supply 210 and the plurality of ports Control 250. More specifically, the control unit 240, upon receiving a power cut-off command and a full cut-off mode command from the OLT 110, cuts off the power supplied to the plurality of ONTs 130 by controlling the power supply 210 Also, all of the plurality of ports 250 are switched to the blocking mode. Here, the blocking mode is to reduce the optical signal through the optical attenuator as described above. Thereafter, the control unit 240 temporarily switches each port 250 to the pass mode sequentially according to a control command from the OLT 110. For example, only the first port 250 is temporarily switched to the pass-through mode and then switched to the blocking mode again, and then only the second port 250 is temporarily switched to the pass-through mode, and then switched to the blocking mode again. The control unit 240 performs such sequential transit mode temporary switching up to the last port 250. If the OLT 110 detects an optical signal from a specific port even though the power is turned off in this process, the control unit 240 blocks the corresponding port according to the blocking command from the OLT 110 and the remaining ports for which the optical signal is not detected. Switches to pass-through mode.

3 is a flowchart illustrating a method of detecting and blocking an unauthorized line in an OLT according to an embodiment of the present invention.

Referring to FIG. 3, in step S301, the OLT 110 determines whether a loss rate or a cyclic redundancy check (CRC) error rate of a packet received from the blocking device 120 or a packet transmitted to the blocking device 120 is greater than or equal to a threshold. . Preferably, the OLT 110 determines whether a loss rate or an error rate of a packet transmitted and received through a port to which the blocking device 120 is connected is greater than or equal to a threshold.

If the packet loss rate or error rate is greater than or equal to the threshold value, in step S302, the OLT 110 transmits a power-off command for all connection lines connected to the blocking device 120 to the blocking device 120. Accordingly, the blocking device 120 cuts off the power supply to all the ONTs 130 connected below it.

In step S303, the OLT 110 transmits a command for switching all ports of the blocking device 120 to the blocking device 120 to the blocking mode. Accordingly, the blocking device 120 switches all ports to which the plurality of ONTs 130 are connected to the blocking mode. Here, the blocking mode is to reduce the optical signal through an optical attenuator included in each port.

In step S304, the OLT 110 sets the variable N to 1, and in step S305 transmits a command for switching the N-th port of the blocking device 120, that is, the first port, to the pass-through mode. Accordingly, the blocking device 120 switches the first port from the blocking mode to the pass mode among the ports to which the plurality of ONTs 130 are connected. That is, the operation of the optical attenuator of the first port is stopped so that the optical signal is not reduced.

In step S306, the OLT 110 checks whether an uplink optical signal is received. Since only the first port of the blocking device 120 is switched to the pass mode, it is checked whether an uplink optical signal is received through the first port. When an uplink optical signal is received, in step S307, the OLT 110 determines the ONT 130 connected to the corresponding first port as an unauthenticated line.

When the detection of the first port is completed in this way, in step S308, the OLT 110 transmits a command to switch the first port back to the blocking mode to the blocking device 120. Accordingly, the blocking device 120 switches the first port back to the blocking mode. Accordingly, all ports of the blocking device 120 are set to the blocking mode.

In step S309, the OLT 110 adds 1 to N, and in step S310, it checks whether N is the maximum value. Here, the maximum value is the number of all ports included in the blocking device 120. If N is not the maximum value, the OLT 110 repeats again from step S305. That is, it is repeated from step S305 to the last port of the blocking device 120 to sequentially check whether there is an unauthenticated line.

When the detection of all ports is completed, in step S311, the OLT 110 transmits a command to switch the other ports to the pass mode except for the ports of the unauthenticated line to the blocking device 120. Accordingly, only the ports of the unauthenticated line are maintained in the blocking mode, and the remaining ports are switched to the pass-through mode, so that normal communication is possible.

In the embodiment with reference to FIG. 3 above, when an uplink optical signal is received from the port in the pass mode in step S307, the OLT 110 determines the ONT 130 connected to the corresponding port as an unauthenticated line. However, according to an embodiment, when an uplink optical signal is received in the pass mode, the OLT 110 may determine whether it is due to a simple transmission error or an unauthenticated ONT 130 to finally determine an unauthenticated line. This will be described with reference to FIG. 4.

4 is a flowchart illustrating a method of detecting and blocking an unauthenticated line in an OLT according to another embodiment of the present invention, and may operate in step S307 of FIG. 3.

Referring to FIG. 4, when an uplink optical signal is received from a port in the pass mode of the blocking device 120, the OLT 110 temporarily determines the ONT 130 connected to the port as an unauthenticated line, and in step S401, Inquire the information of the unauthenticated line. The OLT 110 inquires information of an unauthenticated line by communicating with a network management system that stores subscriber information and subscriber opening processing of a passive optical network.

In step S402, the OLT 110 checks whether the unauthenticated line is a normally opened line, and if the line is not normally opened, the OLT 110 finally determines the unauthenticated line as an unauthenticated line in step S403. . On the other hand, if the unauthenticated line is a normally opened line, in step S404, the OLT 110 checks whether the previously opened registered MAC address of the corresponding line and the MAC address detected from the ONT 130 of the unauthenticated line are the same. . If the MAC addresses are not the same, in step S403, the OLT 110 finally determines the unauthenticated line as an unauthenticated line. On the other hand, if the MAC address is the same, in step S405, the OLT 110 determines that it is a simple transmission error and the corresponding unauthenticated line is finally determined as an authentication line.

While this specification includes many features, such features should not be construed as limiting the scope or claims of the invention. In addition, features described in separate embodiments herein may be combined and implemented in a single embodiment. Conversely, various features described in a single embodiment in the present specification may be individually implemented in various embodiments, or may be properly combined and implemented.

Although the operations have been described in a specific order in the drawings, it should not be understood that such operations are performed in a specific order as shown, or as a series of consecutive sequences, or that all described operations are performed to obtain a desired result. . Multitasking and parallel processing can be advantageous in certain environments. In addition, it should be understood that classification of various system components in the above-described embodiments does not require such classification in all embodiments. The above-described program components and systems may generally be implemented as a package in a single software product or multiple software products.

The method of the present invention as described above may be implemented as a program and stored in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a computer-readable form. This process can be easily carried out by those of ordinary skill in the art to which the present invention pertains, and thus will not be described in detail.

The present invention described above, for those of ordinary skill in the art to which the present invention pertains, various substitutions, modifications and changes are possible within the scope of the technical spirit of the present invention. It is not limited by the drawings.

110: OLT
120: blocking device
130: ONT
210: power supply
220: splitter
230: Communication Department
240: control unit
250: port

Claims (12)

In a system for detecting and blocking an unauthorized line in a passive optical network,
A blocking device comprising a plurality of ports connected to a plurality of optical subscriber terminals, supplying power to the plurality of optical subscriber terminals, and operating the plurality of ports in a blocking mode or a pass mode; And
Whether to receive an uplink optical signal by controlling the blocking device to cut off power to the plurality of optical subscriber terminals and set the plurality of ports to a blocking mode, and then temporarily set each of the plurality of ports to a pass mode sequentially And an optical line terminal for detecting an optical subscriber terminal connected to a port on which an uplink optical signal is received as an unauthenticated line. The method of claim 1,
The blocking device,
A power supply for supplying power to the plurality of optical subscriber terminals;
An optical attenuator provided in each of the plurality of ports to perform the blocking mode or the pass mode; And
And a splitter configured to aggregate uplink optical signals received from the plurality of optical subscriber terminals and transmit them to the optical line terminal, and distribute downlink optical signals received from the optical line terminals to the plurality of optical subscriber terminals. System. The method of claim 2,
The optical line terminal,
A system, characterized in that a port determined as an unauthenticated line is maintained in a blocking mode, and ports of the remaining lines are set in a pass mode. The method of claim 2,
The optical line terminal,
And when the unauthenticated line is in a normal open state and the MAC address detected from the optical subscriber station of the unauthenticated line matches the previously opened MAC address, it is determined as a simple transmission error. The method of claim 4,
The optical line terminal,
If the unauthenticated line is not in a normal open state, or if the MAC address detected from the optical subscriber terminal of the unauthenticated line does not match the previously opened MAC address, it is finally determined as an unauthenticated line. System characterized by. The method of claim 2,
The optical line terminal,
When a loss rate or an error rate of a packet received from the blocking device or a packet transmitted to the blocking device is greater than or equal to a threshold, detecting and blocking an unauthenticated line is initiated. As a method of detecting and blocking unauthorized lines in a passive optical network,
Controls a blocking device that includes a plurality of ports connected to a plurality of optical subscriber terminals, supplies power to the plurality of optical subscriber terminals, and operates the plurality of ports in a blocking mode or a pass mode, and the plurality of optical subscriber terminals Cutting off power to the;
Setting the plurality of ports of the blocking device to a blocking mode;
Temporarily setting each of the plurality of ports of the blocking device to a pass mode sequentially to detect whether an uplink optical signal is received; And
And determining an optical subscriber terminal connected to a port on which an uplink optical signal is received as an unauthenticated line. The method of claim 7,
The blocking device,
A power supply for supplying power to the plurality of optical subscriber terminals;
An optical attenuator provided in each of the plurality of ports to perform the blocking mode or the pass mode; And
And a splitter configured to aggregate uplink optical signals received from the plurality of optical subscriber terminals and transmit them to an optical line terminal, and distribute the downlink optical signals received from the optical line terminals to the plurality of optical subscriber terminals. The method of claim 7,
The determining step,
And maintaining a port determined to be an unauthenticated line in a blocking mode, and setting the ports of the remaining lines in a pass-through mode. The method of claim 7,
The determining step,
And when the unauthenticated line is in a normal open state and the MAC address detected from the optical subscriber station of the unauthenticated line matches the previously opened MAC address, determining as a simple transmission error. The method of claim 10,
The determining step,
If the unauthenticated line is not in a normal open state or is in a normal open state but the MAC address detected from the optical subscriber station of the unauthenticated line does not match the previously opened MAC address, finally determining the unauthenticated line Method comprising a. The method of claim 7,
And when a loss rate or an error rate of a packet received from the blocking device or a packet transmitted to the blocking device is greater than or equal to a threshold value, initiating an operation of detecting and blocking an unauthenticated line.

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